1. Field of the Invention
The present invention relates to a numerical controller, and in particular to a numerical controller having a function of automating a measurement approach by using a camera.
2. Description of the Related Art
When attaching a measuring probe to the head of a machine tool and measuring a workpiece manually using a general-purpose measurement program, the operator performs measurement in accordance with the following procedures.
Procedure 1: Place the workpiece on the bed.
Procedure 2: Select a program for measurement suitable for the shape of the measurement portion of the workpiece.
Procedure 3: Manually move the probe to the measuring object spot for positioning.
Procedure 4: Run the program for measurement.
On the other hand, Japanese Patent Application Laid-open No. 07-210222 A and Japanese Patent Application Laid-open No. 04-164562 A, for example, disclose techniques for moving the tool to a position corresponding to a point designated by the operator on an image of the workpiece surface in plan view captured by an imaging unit as conventional techniques for enabling easy positioning of a tool or the like.
As described above, when manually measuring a workpiece, the operator needs to perform an operation of selecting an appropriate program from a plurality of measurement programs and an operation of moving the probe to the measuring object spot. Such an operation is troublesome for the operator and it is necessary to repeat the selecting operation of the measurement program and the movement operation of the probe when many measuring object spots exist on the workpiece, and there are many cases that the erroneous measurement programs are selected during the repetition.
In the techniques disclosed in Japanese Patent Application Laid-open No. 07-210222 A and Japanese Patent Application Laid-open No. 04-164562 A, although the tool can be moved to a point designated on the captured planar image of the workpiece surface, there is a problem that the position in the Z axis direction cannot be designated. Therefore, in the measurement of an uneven workpiece, there remains a problem that the probe needs to be manipulated manually in the Z direction, which is troublesome for the operator and easily causes a mistake.